- iron or copper pyrites, sometimes mistaken for gold.
Origin of fool's gold
An Americanism dating back to 1870–75
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- any of various yellow minerals, esp pyrite or chalcopyrite, that can be mistaken for gold
- Any of several minerals, especially pyrite and chalcopyrite, sometimes mistaken for gold.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.